Patent Literature 1 discloses an authentication processing device which switches between off-line authentication and on-line authentication, in credit-card settlement, by comparing a settlement money amount with a reference settlement money amount.
Patent Literature 2 discloses an electronic settlement system which separates a balance of a bank account into that for on-line settlement and that for off-line settlement, and then stores the balance for on-line settlement into the normal area of an account file of the bank, and the balance for off-line settlement into an IC (Integrated Circuit) card. This system guarantees a money amount that can be used off-line. The money amount is set and updated by the customer himself/herself by the use of a terminal device.